THE PATHOGENESIS OF QUAIL BRONCHITIS

To determine the fate of virus and characterize the development of les ions, 1-week-old bobwhite quails (Colinus virginianus) were inoculated intratracheally with 10(6) mean tissue-culture-infective doses of qua il bronchitis virus. Quails were killed and necropsied sequentially at 2, 4, 8, 16, and 24 hours postinoculation (PI) and on days 2-10 PI. V irus was first isolated from the lung as early as 2 hours PI, from cec al tonsils and bursa of Fabricius 4 hours PI, and from spleen and live r 8 hours PI. Tissue virus titers were highest on days 4 to 6 PI, corr esponding with the severity of histologic lesions. Viral inclusions we re present in tracheal mucosal epithelium by day 2 PI. On day 3 PI, tr acheal epithelium was deciliated, formed an irregular luminal border, and had more frequent inclusions. On days 4 and 5 PI, tracheal epithel ium was partially desquamated, but there were minimal leukocytic infil trates. Bronchiolar epithelium underwent similar changes, but the leuk ocytic infiltration was more intense and included lymphocytes and hete rophils. There was extension of leukocytic infiltrates into surroundin g lung that was most extensive on day 3 PI. Hyperplasia of splenic mac rophages was first identified on day 2 PI and peaked by day 5 PI.